Abstract: To guarantee construction convenience of the reservoir reinforcement project and ecological security of downstream river channel, it is necessary to investigate the law and control measures of the reservoir bottom sediment discharge during the construction period. Regarding the issues such as eutrophication and ecological degradation of the downstream river channel that might be caused by the reservoir bottom sediment discharge during the construction period of the reservoir reinforcement project, a two-dimensional water and sediment mathematical model was constructed based on the measured topographic and water-sediment data. The sediment concentration at reservoir outlet for different construction schemes was analyzed respectively. Then, in combination with the prototype test, the optimal construction scheme was identified.